/*
 *   CrissCross
 *   A multi-purpose cross-platform library.
 *
 *   A product of Uplink Laboratories.
 *
 *   (c) 2006-2008 Steven Noonan.
 *   Licensed under the New BSD License.
 *
 */

#include <crisscross/universal_include.h>

#ifdef ENABLE_HASHES

#include <crisscross/core_io_reader.h>
#include <crisscross/md4.h>

#define MD4_CTX cc_md4_ctx

typedef unsigned char *POINTER;
typedef const unsigned char *CONST_POINTER;

/* Constants for MD4Transform routine.
 */
#define S11 3
#define S12 7
#define S13 11
#define S14 19
#define S21 3
#define S22 5
#define S23 9
#define S24 13
#define S31 3
#define S32 9
#define S33 11
#define S34 15

static void          MD4Transform(cc_uint32_t [4], unsigned char [64]);
static void Encode(unsigned char *, cc_uint32_t *, unsigned int);
static void Decode(cc_uint32_t *, unsigned char *, unsigned int);

static unsigned char PADDING[64] = {
	0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};

/* F, G and H are basic MD4 functions.
 */
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (y)) | ((x) & (z)) | ((y) & (z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))

/* ROTATE_LEFT rotates x left n bits.
 */
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32 - (n))))

/* FF, GG and HH are transformations for rounds 1, 2 and 3 */
/* Rotation is separate from addition to prevent recomputation */


#define FF(a, b, c, d, x, s) { \
		(a) += F((b), (c), (d)) + (x); \
		(a) = ROTATE_LEFT((a), (s)); \
}
#define GG(a, b, c, d, x, s) { \
		(a) += G((b), (c), (d)) + (x) + (cc_uint32_t)0x5a827999; \
		(a) = ROTATE_LEFT((a), (s)); \
}
#define HH(a, b, c, d, x, s) { \
		(a) += H((b), (c), (d)) + (x) + (cc_uint32_t)0x6ed9eba1; \
		(a) = ROTATE_LEFT((a), (s)); \
}

/* MD4 initialization. Begins an MD4 operation, writing a new context.
 */
/***************************************************************
*
* Procedure MD4Init
*
***************************************************************/
void MD4Init(MD4_CTX *context)
{
	context->count[0] = context->count[1] = 0;

	/* Load magic initialization constants.
	 */
	context->state[0] = 0x67452301;
	context->state[1] = 0xefcdab89;
	context->state[2] = 0x98badcfe;
	context->state[3] = 0x10325476;
}

/* MD4 block update operation. Continues an MD4 message-digest
 *   operation, processing another message block, and updating the
 *   context.
 */
/***************************************************************
*
* Procedure MD4Update
*
***************************************************************/
void MD4Update(MD4_CTX *context, unsigned char *input, unsigned int inputLen)
{
	unsigned int i, index, partLen;

	/* Compute number of bytes mod 64 */
	index =      (unsigned int)((context->count[0] >> 3) & 0x3F);
	/* Update number of bits */
	if ((context->count[0] += ((cc_uint32_t)inputLen << 3))
	    < ((cc_uint32_t)inputLen << 3))
		context->count[1]++;

	context->count[1] += ((cc_uint32_t)inputLen >> 29);

	partLen = 64 - index;


	/* Transform as many times as possible.
	 */
	if (inputLen >= partLen) {
		memcpy
		                                                                                                                                              ((POINTER)&context->buffer[index], (POINTER)input, partLen);
		MD4Transform(context->state, context->buffer);

		for (i = partLen; i + 63 < inputLen; i += 64)
			MD4Transform(context->state, &input[i]);

		index = 0;
	} else
		i = 0;

	/* Buffer remaining input */
	memcpy
	                                                                                                                                              ((POINTER)&context->buffer[index], (POINTER)&input[i],
	                                                                                                                                              inputLen - i);
}

/* MD4 finalization. Ends an MD4 message-digest operation, writing the
 *   the message digest and zeroizing the context.
 */
/***************************************************************
*
* Procedure MD4Final
*
***************************************************************/
void MD4Final(unsigned char digest[16], MD4_CTX *context)
{
	unsigned char bits[8];
	unsigned int  index, padLen;

	/* Save number of bits */
	Encode(bits, context->count, 8);

	/* Pad out to 56 mod 64.
	 */
	index =       (unsigned int)((context->count[0] >> 3) & 0x3f);
	padLen = (index < 56) ? (56 - index) : (120 - index);
	MD4Update(context, PADDING, padLen);

	/* Append length (before padding) */
	MD4Update(context, bits, 8);
	/* Store state in digest */
	Encode(digest, context->state, 16);

	/* Zeroize sensitive information.
	 */
	memset((POINTER)context, 0, sizeof(*context));
}

/* MD4 basic transformation. Transforms state based on block.
 */
/***************************************************************
*
* Procedure MD4Transform
*
***************************************************************/
static void MD4Transform(cc_uint32_t state[4], unsigned char block[64])

{
	cc_uint32_t a = state[0], b = state[1], c = state[2], d = state[3], x[16];

	Decode(x, block, 64);

	/* Round 1 */
	FF(a, b, c, d, x[ 0], S11);    /* 1 */
	FF(d, a, b, c, x[ 1], S12);    /* 2 */
	FF(c, d, a, b, x[ 2], S13);    /* 3 */
	FF(b, c, d, a, x[ 3], S14);    /* 4 */
	FF(a, b, c, d, x[ 4], S11);    /* 5 */
	FF(d, a, b, c, x[ 5], S12);    /* 6 */
	FF(c, d, a, b, x[ 6], S13);    /* 7 */
	FF(b, c, d, a, x[ 7], S14);    /* 8 */
	FF(a, b, c, d, x[ 8], S11);    /* 9 */
	FF(d, a, b, c, x[ 9], S12);    /* 10 */
	FF(c, d, a, b, x[10], S13);    /* 11 */
	FF(b, c, d, a, x[11], S14);    /* 12 */
	FF(a, b, c, d, x[12], S11);    /* 13 */
	FF(d, a, b, c, x[13], S12);    /* 14 */
	FF(c, d, a, b, x[14], S13);    /* 15 */
	FF(b, c, d, a, x[15], S14);    /* 16 */

	/* Round 2 */
	GG(a, b, c, d, x[ 0], S21);    /* 17 */
	GG(d, a, b, c, x[ 4], S22);    /* 18 */
	GG(c, d, a, b, x[ 8], S23);    /* 19 */
	GG(b, c, d, a, x[12], S24);    /* 20 */
	GG(a, b, c, d, x[ 1], S21);    /* 21 */
	GG(d, a, b, c, x[ 5], S22);    /* 22 */
	GG(c, d, a, b, x[ 9], S23);    /* 23 */
	GG(b, c, d, a, x[13], S24);    /* 24 */
	GG(a, b, c, d, x[ 2], S21);    /* 25 */
	GG(d, a, b, c, x[ 6], S22);    /* 26 */
	GG(c, d, a, b, x[10], S23);    /* 27 */
	GG(b, c, d, a, x[14], S24);    /* 28 */
	GG(a, b, c, d, x[ 3], S21);    /* 29 */
	GG(d, a, b, c, x[ 7], S22);    /* 30 */
	GG(c, d, a, b, x[11], S23);    /* 31 */
	GG(b, c, d, a, x[15], S24);    /* 32 */

	/* Round 3 */
	HH(a, b, c, d, x[ 0], S31);    /* 33 */
	HH(d, a, b, c, x[ 8], S32);    /* 34 */
	HH(c, d, a, b, x[ 4], S33);    /* 35 */
	HH(b, c, d, a, x[12], S34);    /* 36 */
	HH(a, b, c, d, x[ 2], S31);    /* 37 */
	HH(d, a, b, c, x[10], S32);    /* 38 */
	HH(c, d, a, b, x[ 6], S33);    /* 39 */
	HH(b, c, d, a, x[14], S34);    /* 40 */
	HH(a, b, c, d, x[ 1], S31);    /* 41 */
	HH(d, a, b, c, x[ 9], S32);    /* 42 */
	HH(c, d, a, b, x[ 5], S33);    /* 43 */
	HH(b, c, d, a, x[13], S34);    /* 44 */
	HH(a, b, c, d, x[ 3], S31);    /* 45 */
	HH(d, a, b, c, x[11], S32);    /* 46 */
	HH(c, d, a, b, x[ 7], S33);    /* 47 */
	HH(b, c, d, a, x[15], S34);    /* 48 */

	state[0] += a;
	state[1] += b;
	state[2] += c;
	state[3] += d;

	/* Zeroize sensitive information.
	 */
	memset((POINTER)x, 0, sizeof(x));
}

/* Encodes input (cc_uint32_t) into output (unsigned char). Assumes len is
 *   a multiple of 4.
 */
/***************************************************************
*
* Procedure Encode
*
***************************************************************/
static void Encode(unsigned char *output, cc_uint32_t *input, unsigned int len)
{
	unsigned int i, j;

	for (i = 0, j = 0; j < len; i++, j += 4) {
		output[j] =     (unsigned char)(input[i] & 0xff);
		output[j + 1] = (unsigned char)((input[i] >> 8) & 0xff);
		output[j + 2] = (unsigned char)((input[i] >> 16) & 0xff);
		output[j + 3] = (unsigned char)((input[i] >> 24) & 0xff);
	}
}

/* Decodes input (unsigned char) into output (cc_uint32_t). Assumes len is
 *   a multiple of 4.
 */
/***************************************************************
*
* Procedure Decode
*
***************************************************************/
static void Decode(cc_uint32_t *output, unsigned char *input, unsigned int len)
{
	unsigned int i, j;

	for (i = 0, j = 0; j < len; i++, j += 4)
		output[i] = ((cc_uint32_t)input[j]) | (((cc_uint32_t)input[j + 1]) << 8) |
		            (((cc_uint32_t)input[j + 2]) << 16) | (((cc_uint32_t)input[j + 3]) << 24);
}

namespace CrissCross
{
	namespace Crypto
	{
		MD4Hash::MD4Hash() : m_hashString(NULL), m_hash(NULL)
		{
			Reset();
		}

		MD4Hash::~MD4Hash()
		{
			Reset();
		}

		int MD4Hash::Process(const void * _data, size_t _length)
		{
			Reset();
			if (!_data) return -1;

			MD4Update(&m_state, (unsigned char *)_data, _length);
			m_hash = new unsigned char[MD4_DIGEST_LENGTH];
			MD4Final((unsigned char *)m_hash, &m_state);
			return 0;
		}

		int MD4Hash::Process(CrissCross::IO::CoreIOReader *_reader)
		{
			Reset();
			if (!_reader) return -1;

			cc_int64_t pos = _reader->Position();
			_reader->Seek(0);
			char       buffer[8192]; int bytesRead = 0;
			do
			{
				bytesRead = _reader->Read(buffer, sizeof(buffer), 0, sizeof(buffer));
				if (bytesRead >= 0)
					ProcessBlock(buffer, bytesRead);
			} while (bytesRead == sizeof(buffer) && !_reader->EndOfFile());
			Finalize();
			_reader->Seek(pos);
			return 0;
		}

		int MD4Hash::ProcessBlock(const void * _data, size_t _length)
		{
			if (!_data) return -1;

			MD4Update(&m_state, (unsigned char *)_data, _length);
			return 0;
		}

		void MD4Hash::Finalize()
		{
			if (m_hash) delete [] m_hash;

			m_hash = new unsigned char[MD4_DIGEST_LENGTH];
			MD4Final((unsigned char *)m_hash, &m_state);
		}

		const char *MD4Hash::ToString() const
		{
			if (m_hashString) return m_hashString;

			m_hashString = new char[33];
			for (int i = 0; i < MD4_DIGEST_LENGTH; i++)
				sprintf(m_hashString + (i * 2), "%02x", m_hash[i]);

			return m_hashString;
		}

		void MD4Hash::Reset()
		{
			delete [] m_hash; m_hash = NULL;
			delete [] m_hashString; m_hashString = NULL;

			MD4Init(&m_state);
		}

		bool MD4Hash::operator==(const MD4Hash &_other) const
		{
			return (memcmp(m_hash, _other.m_hash, MD4_DIGEST_LENGTH) == 0);
		}
	}
}

#endif
